1月30日,美国研究人员宣布,人脑语言处理中枢并不位于大脑皮层后部,科学界关于这一问题的认识长期以来是“错误”的。
论文作者、美国乔治敦大学医学中心教授约瑟夫·劳施埃克当天在一份新闻公报中说,100多年的旧理论被推翻,“教科书将需要改写”。
19世纪末,研究脑损伤和中风的德国医生韦尼克提出,人脑语言处理中枢在大脑皮层后部,位于感知声音的听觉皮层之后。这一观点已被科学界广泛接受,人脑语言处理中枢也因此被称为韦尼克区。
但劳施埃克和其同事对使用多种脑成像技术的115项语言感知研究进行评估后认为,真正的韦尼克区(Wernicke's area Wikipedia)位于听觉皮层之前,与前脑仅有3厘米左右的距离。他们的论文本周发表在《国家科学院院刊》网络版上。
研究人员介绍说,自20世纪90年代认识神经科学兴起以来,科学家发现了有关韦尼克区的不少矛盾之处,但多数人还是不愿否认已有100多年历史的旧理论,而这篇“论文就是要让数据和理论之间形成一致”。
确定人脑语言处理中枢真正所在将有重要的临床价值。劳施埃克说:“当有病人说不了话或发生语言理解困难时,我们现在将能很好地知道哪里受到了伤害。”(生物谷 Bioon.com)
doi:10.1073/pnas.1113427109
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Phoneme and word recognition in the auditory ventral stream
Iain DeWitt and Josef P. Rauschecker
Spoken word recognition requires complex, invariant representations. Using a meta-analytic approach incorporating more than 100 functional imaging experiments, we show that preference for complex sounds emerges in the human auditory ventral stream in a hierarchical fashion, consistent with nonhuman primate electrophysiology. Examining speech sounds, we show that activation associated with the processing of short-timescale patterns (i.e., phonemes) is consistently localized to left mid-superior temporal gyrus (STG), whereas activation associated with the integration of phonemes into temporally complex patterns (i.e., words) is consistently localized to left anterior STG. Further, we show left mid- to anterior STG is reliably implicated in the invariant representation of phonetic forms and that this area also responds preferentially to phonetic sounds, above artificial control sounds or environmental sounds. Together, this shows increasing encoding specificity and invariance along the auditory ventral stream for temporally complex speech sounds.